1. Field of the Invention
This invention relates to an intake air heater for a gasoline fuel containing alcohol.
2. Description of the Prior Art
An intake air heater controls an amount of air being heated in an intake system, so as to facilitate the warming-up of an engine when the engine is at a low temperature, as well as promote atomization of a fuel. A prior art intake air heater, however, has been confronted with a difficulty where, for example, Gashol (a gasoline containing 10% of ethyl alcohol) is used as a fuel, because the latent heat of alcohol pertaining to evaporation per a certain heating valve is about seven times as large as that of gasoline. If the amount of air being heated is determined in the same manner as for a pure gasoline fuel, i.e., independently of the concentration of alcohol, as in the prior art intake air heater, if a gasoline fuel containing alcohol is employed, poor atomization results, thus impairing the safety running of an engine.